A3 2.0 FSI 2003 Stalling after working for some time

[Onumara]

Hello there people

 

I find myself here today after what i would consider at this point a "traumatic experience" in my A3

 

The car is a 2003 A3 8P 2.0 FSI with soon to be 330k km, and am having quite serious issues with it.

 

I had oil-water mixing, immediatly thinking my head gasket was done for, which prompted me to replace it myself, which was tedious but got done for in about a month or so

Though it was actually not the culprit, as the head gasket was actually fine, but a gasket in the oil cooler that had to be replaced and was the cause of the oil water mixing

I had the head rectified while i was at it, had an injector break because of it but found one quite cheap

 

Quite a bit annoyed, i was finally done about a week ago with the car, and started enjoying it again, quite a singing thing with the exhaust i put on it and not slow either, very happy with the result, just until towards the end of the test drive.

Letting the car warm up, finally getting some revs in, i get back home with a big smile on my face just until the car stalls right in front of my house, and doesn't restart until about 3 or 4 minutes of waiting, after what it goes back on without any strange noise

I look past this little fluke, and go about the week of work when i take it back for a spin.

 

The car feels great still, no rough idle, warms up nicely, cooling fans working properly in temps, revs beautifully and pushes out all of its healthy horses, after some driving though, i get a check engine light but no symptoms in engine sound or feeling, i scoff it off and go about the day knowing some sensors are to be replaced and it must be just that, after what i also get a red battery warning which is odd as i charged the battery back to full the day before this drive and the alternator was still working.

 

All is good again, the car drives nicely until late at night on the way home, the car suddenly stalls like it did after the first test drive with a daunting Red oil pressure warning, where i litteraly shat myself.

Having made all the basic maintenance after all the jazz with the head gasket, i knew oil, coolant and all was good, so looked for traces of oil in the engine bay and on the roads i've driven.

Nothing in the bay, nothing on the roads, the oil was there so no way i had an oil leak somewhere.

I nurse the car back home, waiting for it for a while, driving it very slowly and stalling about 4 times on the way back home, gladly it was not too far, about 3 km.

All the while the check engine mentionned before was gone, the red battery issue was coming on and off but stayed mostly on and the car always stalled for lack of oil pressure or i hope not actually and it's just the sensor that's !Removed!.

Finally got it back home, car had one misfire towards the end and started running rough, let it sleep for the night and started it again the day after to be greeted with an uneven and rough idle with very few but present misfires, almost the same as when i had found out about the !Removed! injector earlier.

 

Oil level is fine, oil itself seems fine too (clean), no smoke coming from the exhaust, the battery symbol still on and the check engine gone, i am now wondering what the hell just went wrong with car, and am asking for you guys's insight

 

I think and pray that it is just a sensor that went awry, and some clues do point towards this, like how the rev counter was locked at 6k at some point and only came back when i last stalled it the night and waited 15 mins this time, like some wiring or the sensor itself was too hot to work and managed to gather back its head after cooling for a longer while.

I am certain i remounted the engine fine, as it did work fine for a while but again, i don't really know where to look at

What do you guys think went wrong ? I would really appreciate any form of help

 

Thanks in advance,

One scared !Removed!.

[Stevey Y]

1 hour ago, Onumara said:

Hello there people

 

I find myself here today after what i would consider at this point a "traumatic experience" in my A3

 

The car is a 2003 A3 8P 2.0 FSI with soon to be 330k km, and am having quite serious issues with it.

 

I had oil-water mixing, immediatly thinking my head gasket was done for, which prompted me to replace it myself, which was tedious but got done for in about a month or so

Though it was actually not the culprit, as the head gasket was actually fine, but a gasket in the oil cooler that had to be replaced and was the cause of the oil water mixing

I had the head rectified while i was at it, had an injector break because of it but found one quite cheap

 

Quite a bit annoyed, i was finally done about a week ago with the car, and started enjoying it again, quite a singing thing with the exhaust i put on it and not slow either, very happy with the result, just until towards the end of the test drive.

Letting the car warm up, finally getting some revs in, i get back home with a big smile on my face just until the car stalls right in front of my house, and doesn't restart until about 3 or 4 minutes of waiting, after what it goes back on without any strange noise

I look past this little fluke, and go about the week of work when i take it back for a spin.

 

The car feels great still, no rough idle, warms up nicely, cooling fans working properly in temps, revs beautifully and pushes out all of its healthy horses, after some driving though, i get a check engine light but no symptoms in engine sound or feeling, i scoff it off and go about the day knowing some sensors are to be replaced and it must be just that, after what i also get a red battery warning which is odd as i charged the battery back to full the day before this drive and the alternator was still working.

 

All is good again, the car drives nicely until late at night on the way home, the car suddenly stalls like it did after the first test drive with a daunting Red oil pressure warning, where i litteraly shat myself.

Having made all the basic maintenance after all the jazz with the head gasket, i knew oil, coolant and all was good, so looked for traces of oil in the engine bay and on the roads i've driven.

Nothing in the bay, nothing on the roads, the oil was there so no way i had an oil leak somewhere.

I nurse the car back home, waiting for it for a while, driving it very slowly and stalling about 4 times on the way back home, gladly it was not too far, about 3 km.

All the while the check engine mentionned before was gone, the red battery issue was coming on and off but stayed mostly on and the car always stalled for lack of oil pressure or i hope not actually and it's just the sensor that's !Removed!.

Finally got it back home, car had one misfire towards the end and started running rough, let it sleep for the night and started it again the day after to be greeted with an uneven and rough idle with very few but present misfires, almost the same as when i had found out about the !Removed! injector earlier.

 

Oil level is fine, oil itself seems fine too (clean), no smoke coming from the exhaust, the battery symbol still on and the check engine gone, i am now wondering what the hell just went wrong with car, and am asking for you guys's insight

 

I think and pray that it is just a sensor that went awry, and some clues do point towards this, like how the rev counter was locked at 6k at some point and only came back when i last stalled it the night and waited 15 mins this time, like some wiring or the sensor itself was too hot to work and managed to gather back its head after cooling for a longer while.

I am certain i remounted the engine fine, as it did work fine for a while but again, i don't really know where to look at

What do you guys think went wrong ? I would really appreciate any form of help

 

Thanks in advance,

One scared !Removed!.

Hi the only way you will find a clue to what is going on is to have the car scanned with VCDS or similar.

Steve.

[cliffcoggin]

I agree you need the car scanned by a decent code reader, however the battery warning light may be a clue. A substandard battery can cause all the symptoms you describe and a few more that you have not. I assume the battery was disconnected during your repair work. Did it lose charge during that time?

[Onumara]

Thank you both for your answers,

To answer you Steve, yea the code reading is on the way, will keep you posted on it

And yea Cliff, the battery was disconnected but also discharged as i checked compression and stuff during remounting, but that same battery was in it before the head gasket episode, can it really die on one full discharge like that ?

Thanks again, back here as soon as i got news

[cliffcoggin]

A battery that is fully or largely discharged can be damaged in such a way as to be able to still crank the engine over but not supply a stable enough voltage to the electronics, which can lead to the sort of problems you reported. I am not saying the battery is entirely responsible for those problems, but it is a strong contender.

See what the code reader tells you before doing anything.

[Onumara]

So... back after code reading and more testing, and it's clearly a case of hasty engineering with barely out the oven and not finished electronics...

The battery is fine, dad tested it on another car with no issues whatsoever, so i am quite sure it isn't the problem

 

Code reading gave no new codes, only those i had before but i also found out the red battery symbol was always there, it really just comes and goes as it pleases and it was here this time

I had my father give me this car too by the way, there are some warnings and all that piled up since he had the car, but being a mechanic he knew which ones was bad and those that were serious, i just now had that battery symbol and my father had it all the time he had the car so it should not be the culprit

 

Anyways, after clearing all the codes, the car got its behaviour back as usual, meaning rocky start for the 30 first seconds then back to normal idle, power present and no strange behaviours like smoke or anything coming out from anywhere

My dad and I are about sure there is a sensor f ing up after the car ran for some time, as with codes removed, the car easily went about the day without any bad surprises (Just have to make sure the car stayed a night outside to cool whatever is f ing up before clearing the codes)

Though that sensor seems to be holding on for dear life, as you really need to drive for a while for it to give in and stop working, but it's like the car doesn't record the failure.

For now, my dad seems to think the crankshaft position sensor is faulty, go figure as the car showed the oil pressure warning when it stalled, so that's where i would be looking first, but we don't know which one is it so for now we search

I work close to home, so i use the car to last me the day and avoid long drives if i can't push the car over to home, been going fine for now, will keep you guys posted

 

[cliffcoggin]

The solution is simple: you need a new battery, however you and your father have convinced yourselves that the existing battery is fine, so I don't propose to argue any further.

[Onumara]

Well, we finally found out what it was

Guess what

Faulty sensor it was, crankshaft position sensor rusted, held up just until you warmed it up and after reusing the car since then, worsenned even further

We also suspect oil pressure warning to be the sensor too, and seeing how it's just next to the crankshaft one, no detective work needed to figure it out, they both rusted, which is angering how it could happen but whatever, case closed at least

 

At this point, when it's German or recent, check if the sensor is doing its work before doing anything else.

Yea it was crankshaft sensor being done,